Prime mover for wheel chairs



July 25, 1961 R. H. KLAPPERT PRIME MOVER FOR WHEEL CHAIRS 5 Sheets-Sheet1 Filed May 9, 1958 INVENTOR.

RICH ARD H. KLAPPERT BY July 25, 1961 R. H. KLAPPERT 2,993,550

PRIME MOVER FOR WHEEL CHAIRS Filed May 9, 1958 5 Sheets-Sheet 2 z'y. Z.

l l/ 22 2 6 i I i fig: 202

H 64 mum. n f2 INVENTOR.

RICHARD H. KLAPPERT ATTORNEY July 25, 1961 R. H. KLAPPERT PRIME MOVERFOR WHEEL CHAIRS 5 Sheets-Sheet 3 RICHARD H. KLAPPERT ATTORNEY July 25,1961 KLAPPERT 2,993,550

PRIME MOVER FOR WHEEL CHAIRS Filed May 9, 1958 5 Sheets-Sheet 4INVENTOR.

RICHARD H. KLAPPERT 77M @MM ATTORNEY July 25, 1961 R. H. KLAPPERT PRIMEMOVER F QR WHEEL CHAIRS 5 Sheets-Sheet 5 Filed May 9, 1958 INVENTOR.RlcH'A'fio H. KLAPPERT 772M 5 ATTORNEY the chair.

United States Patent 2,993,550 PRIME MOVER FOR WHEEL CHAIRS Richard H.Klappert, Tucson, Ariz., assignor to Aidco, Tucson, Ariz., a limitedpartnership Filed May 9, 1958, Ser. No. 734,259 3 'Claims. (Cl. 180-15)-moved from standard, folding type wheel chairs.

Another object of the invention is to provide means of the typedescribed wherein the occupant of a wheel chair can control a pluralityof forward and reverse speeds and turning movements of the chair with asingle control rod.

Another object of the invention is to provide a prime mover for wheelchairs and the like having a simple and .novel means for impartingdifferential speeds to the driving wheels of the prime mover on the onehand, while utilizing a single axle on the other hand.

A further object of the invention is to provide a prime mover of thetype described including a wheeled frame, a

guide wheel for the frame, and unitary control means adapted to beconnected to a Wheel chair for controlling forward, reverse and turningmovements of the wheel chair.

A further object of the invention is to provide a prime mover for wheelchairs and the like that is simple and practical in construction, has alow center of gravity, is

strong and reliable in use, is neat and attractive in appearance, isrelatively inexpensive to manufacture, and

otherwise well adapted to the purposes for which the same 1 is intended.

Another object of the invention is to provide novel means for attachinga prime mover to a wheel chair whereby vibrations and vertical impactsimparted to said prime mover will not be transmitted to said chair.

and inexpensive means for controlling the operation of aprime mover witha single control lever.

A further object of the invention is to provide a novel switch forcontrolling the electrical circuit of a prime mover.

Other objects and advantages of the invention reside in the details ofconstruction and operation as more fully hereinafter described andclaimed.

While motorized wheel chairs are known and are generally satisfactory,they do have some drawbacks. The;

major'drawback resides in thefact that the motorized units areincorporated into the chair as a more or less permanent part thereofwhich makes it difficult, and quite often impossible, to fold the chairfor easy storage and transportation thereof. sometimes adapted to drivethe large wheels of the chair -by frictional contact therewith whichresults in slippage and inability toimpart positive hill climbingability to If the motorized units are not adapted to frictionally driveeach wheel of the chair, expensive differential means or separate axlesfor each wheel must be provided.

,My invention overcomes these and other drawbacks aswill be apparentfrom the description and claims which The invention will be readilyunderstood by reference 1 Another object of the invention is to providea simple.

Patented July 25, 1961 FIG. 1 is a side elevational view showing a primemover of my invention attached to a wheel chair;

FIG. 2 is a plan view of the prime mover of my invention with its coverremoved;

FIG. 3 is a side elevational view of the prime mover of my inventionwith its cover partially broken away;

FIG. 4 is a plan view partly in section, of a control lever forcontrolling the operation of the prime mover;

FIG. 5 is a perspective view of the electrical switch for controllingthe electrical system shown in FIGURE 6;

FIG. 6 is a schematic diagram illustrating the electrical system for theprime mover shown in FIGURES 2 and 3;

FIG. 7 is a front elevational view of a portion of the apparatus shownin FIGURE 1;

FIG. 8 is a perspective view of a portion of the paratus shown in FIG.7; and

FIG. 9 is a cross-sectional view, partly in elevation, of details of thecontrol lever taken on the line 99 in FIGURE 4.

Referring now to FIGS. 1 and 7 of the drawings, a wheel chair A, of thewell known folding type, includes an X-brace B and an upstanding post C.A prime mover 10, having a hood or cover 11, is held in drivingengagement with the chair A by means of U-shaped brackets 12, each ofwhich has a back plate 13 and a pin 13a. The back plates 13 push againstthe X-brace B to move the chair A forward and the pins 13a pull againstthe X-brace B to pull the chair A in a reverse direction. Sufiicientspace is maintained betweenback plate 13 and pins 13a to permit thebrackets 12 to move freely along the longitudinal axes of the X-brace Bso that vibrations and impacts imparted to prime mover 10 will not betransmitted to the chair A. This feature also permits the prime mover 10to rise and fall with rough spots in the ground over which it travelswithout jarring or tipping chair A.

Each pin 13a has a head 14 and a cut-out portion 14a adapted to passthrough the slotted portion of a slotted-hole 15 (FIG. 8). Each pin 13aalso has a spring 16 which biases the pin 13a against being dislodgedfrom slotted-hole 15. The operator of the wheel chair A can readilyattach the prime mover 10 thereto While remaining in the chair A bybacking it over the prime mover 10 so that the X-brace B is inengagement with the brackets 12. The pins 13a are then pulled up. sothat the cut-out portions 14a of the pins 13a pass through the slottedportions of slotted-holes 15. The pins 13a are then released and theportions of the pins 13:: which are above the cut-out portions 14aengage the circular portions of the slotted-holes 15.

The prime mover 10 is controlled through a control ibox 72 which isattached to the upstanding post C Also, the motorized units are;

'on the chair A and which will be hereinafter described.

Referring to FIGSv 2 and 3, the prime mover 10includes a main frame 20having an upstanding front wall secured to the bottom 23 of the frame20* by any suitable means, not shown. Although any suitable motors maybe used, I prefer to use standard 6 volt automobile generators havingtheir fields in series and their armatures in parallel. Sprockets orpulleys 32 and 33 are afiixed to the shafts 34 and 35 of the motors 30and 31, respectively. The motors 30 and 31 are controlled in a mannerand by means to be hereinafter explained.

A shaft 40 is rotatably mounted on frame 20 in pillow blocks 41 and 42.A sprocket or pulley 43 is rigidly affixed to shaft 40 and a sprocket 44is rotatably mounted thereon. A sprocket 45 is rigidly atfixed torotatable sprocket 44 by any suitable means, such as welding.

Wheels 46 and 47 rotat-ably mounted on opposed ends of a fixed shaft oraxle 48 and sprockets or pulleys 49 and 49a are affixed to the wheels 46and 47, respectively.

motor 30 drives the wheel '46 by rotation of sprocket or pulley 32 whichdrives sprocket 43 and the shaft 40 through chain or belt 50. Rotationof shaft 40 causes chain 51 to drive the wheel 46.

A third chain or belt 53 is trained about the sprocket 33 of the motor31 and the sprocket 44 which is rotatably mounted on the shaft 40. Afourth chain or belt 54 is trained about the sprocket pulley 45 which isrigidly aflixed to rotatable sprocket 44 and the sprocket or pulley 49awhich is afiixed to the wheel 47.

The motor 31 drives the wheel 47 through the rotation of sprockets 44and 45 as a unit on shaft 40 which, in turn, rotates the wheel 47through sprocket 49a by means of chain 4.

The sprocket 43 has been rigidly afiixed to the retatable shaft 40 whilethe sprockets 44 and 45 rotate thereon as a unit to provide a universalor differential effect when the prime mover turns corners. Thedifferential action permits one wheel 46 or 47 to turn faster than theother wheel 46 or 47.

While other means for transmitting power to the wheels 46 will manifestthemselves, I prefer to use the drive arrangements shown because of itssimplicity, inherent low friction and free-wheeling ability. Worm geardrives could be used, but have the drawback that an extra large currentis required to overcome their frictional resistance and also because itis extremely diflicult to push the chair by hand with such a unitattached thereto.

The motors 30 and 31 and also the batteries 201 and 202 ('FIG. 6) aremounted between the wheels 46 and 47 so that the frame 20 can be veryclose to the ground, thereby giving the prime mover 10 a very low centerof gravity. When the prime mover 10 is used for propelling wheel chairs,the low center of gravity of the prime,

mover 10 minimizes any tendency of the wheel chair to upset and givesthe user of the chair a better sense of security against tipping overthan would be the case if the prime mover 10 had a high center ofgravity.

A tiller wheel 60 is mounted in a bifurcated portion 61 which has ashaft 62 rotatably mounted in a bearing 63. The tiller wheel 60 ispivoted by means of a first link 64 rigidly aflixed to the bifurcatedportion 61; a second link 65 which has one end pivotally connected tothe first link 64, and its other end pivotally connected to a third link67 which is rigidly connected to an upstanding rod 66; and a fourth link67a which has oneend rigidly connected to the lower end of rod 66 andits other end pivotally connected to a cable 70. The upstanding rod 66is pivotally mounted in knuckles 68 which are afiixed to the front wall21 of frame 20. The tiller wheel 60 is controlled through the cable 70which is encased in a flexible housing 71 and is controlled through thecontrol box 72 shown in FIGURE 1.

Referring now to FIG. 4 the control box 72 includes a bottom wall 72a,ball and socket joint 73 is mounted in said box 72 by any suitablemeans, not shown. A handle or rod 74 is attached to a bracket 75 by anysuitable means, not shown. The bracket 75 includes legs 75a and 75bwhich lie at right angles toeach other in a horizontal plane. Thebracket 75 is attached to the balland-socket joint 73 by means of afirst pin 77, nuts 77a and ferrules 77b. A second pin 76 is rigidlysecured to the bracket 75, as shown in FIG. 4. Clevises 78 and 78a arerotatably mounted on the pins 76 and 77 The clevis 78 has a shaft 79slidably engaging elongated, holes 80 in the end thereof, and the clevis78a has a shaft 79a 4. loosely mounted in elongated holes a in the endthereof. An upstanding rod 81 prevents longitudinal movement of shaft79a, but permits vertical movement thereof through hole 81a in shaft79a. The tiller cable 70 is rigidly afiixed to the shaft 79 and acontrol cable 82 is rigidly affixed to the shaft 79a. The sliding shafts79 and 79a and the mounting of the handle 74 on the ball and socketjoint 73 makes it possible to simultaneously move both cables 70 and 82by moving the lever 74 both sidewise and forward (or backward as thecase may be) on a sort of arc. The control box 72 may be attached to thewheel chair A by any suitable means such as a clamp 83 which includes aU-shaped portion 83a having a bar or strap 84 hingedly mounted on oneleg thereof. The strap 84 carries a threaded bolt 84a. The U-shapedportion 83a of the clamp 83 engages the upstanding post C of wheel chairA and the strap 84 is then swung shut and retained in contact with thepost C adjacent the U-shaped portion 83a by threading the bolt 84!: intoa nut 85. Resilient pads 88 are provided as shown, to assure a firm gripof the clamp 83a to the post C.

The control box 72 also carries an interlock switch 86 which isdepressed when the control box 72 is attached to the chair A. Theinter-lock switch 86 must be depressed before a circuit can be completedto the motors 30 and 31. In addition, the control box carries a toggleswitch 87 which must be thrown to its on position before a circuit canbe completed to the motors 30 and 31. Thus, the control lever 74 willnot activate the motors 30 and 31 unless both the interlock 86 and thetoggle switch 87 are in their on positions.

Electrical current to the motors 30 and 31 is controlled through aswitch 90 (FIGS. 5 and 6) which may be located in any suitable place,such as on wall 22 within the prime mover 10 super-jacent the bottomportion 23, not shown. The switch 90 is a six position, four pole,sliding contact type switch having a base 91 on which is mounted fourbus bars 92, 93, 94, and 95. The busbar 92 is divided into segments 96,97, 99 and 100. The segments are separated by suitable insulators 98 and101. A conductor 102 connects segment 96 to segment and a conductor 103connects segments 97 and 99 together. The bus bar 93 is divided intosegments 105, and 107 which are separated by insulator 98. The bus bar94 is divided into segments 112, 113, and which are separated byinsulators 98 and 101. A conductor connects segment 107 of bus bar 93with segment 113 of bus bar 94 and a conductor 121 connects segment 105of bus bar 93 with segment 115 of bus bar 94. The bus bar 95 is dividedinto segments 124 and 126 which are separated by insulator 98. Segments124 and 126 of bus bar 95 are connected together by a conductor 130.Contact carriers 132 and 133 are made of, electrical conducting materialand are attached to an insulated bar 134. Each contact carrier is splitinto prongs 135 and 136 near the end remote from the bar, 134. Eachprong has a self-cleaning type contact 137 afiixed thereto. The contacts137 slidably engage the bus bars and are maintained in position thereonby covers 138, only one of which is shown, which are afiixed to the baseplate 91 by any suitable means, such as screws 139. The switch 90 ispositioned by cable 82 which engages hole 90a and provides a neutralposition where no current will flow therethrough when the contacts 137are riding on the insulators 98, and five current-flowing positions whenthe contacts selectively engage segment groups -100107115126,99-107-115126, 97 105-113-124, 96-105113-124 and 96105- 112-124,respectively.

Twelve volt, D.C. electrical power is supplied to the motors 30 and 31through the electrical system shown in FIG. 6, wherein the numeral 200represents a. 12 -vol-t source of power which in my preferred embodimentcomprises two six volt batteries 201 and 202 connected in throughconductors 208 and 209 with the toggle switch 87 and segment 124 of busbar 95. The negative side L2 of the power source 200 is connectedthrough conductor 210 to one endof the coil of a second solenoid orrelay 211 which has the normally open pole 212. The other end of thecoil of relay 211 is connected through conductor 213 to the segment 96of bus bar 92.

The relay 205 has a contact 214 which is superjacent the pole 206 andwhich is connected through conductors 215 and 215a to the contactcarrier 132 of switch 90. The relay 211 has a contact 216 which issuperjacent the pole 212 and which is connected to one brush 217 of eachmotor 30 and 31 through conductors 218 and 219, respectively. Thenegative side L2 of the power source 200 is connected through conductors220 and 220a to the contact carrier 133 of switch 90.

The other brushes 221 of the motors 30 and 31 are connected to thenegative side L2 of the power source 200 through conductor 220. One sideof a resistance grid 226 is connected through conductors 227 and 228 tothe pole 212 of the relay 211 and to the contact 214 of relay 205through conductors 227, 229 and 215. The other side of the resistancegrid 226 is connected through conductors 230 and 218 to the contact 216of relay 211 and through conductors 230, 218 and 219 to the brushes 217of motors 30 and 31.

The field coils 231 and 232 of the motors 30 and 31 are connectedtogether in series through conductor 233, to segment 105 of bus bar 93through conductor 234, and to segment 113 of bus bar 94 throughconductors 235 and 236. A resistance 237 of approximately 8 ohms isconnected between segment 112 of bus bar 94 and the field coils 231 and232 through conductors 238, 239 and 235.

Operation of the device will be readily understood.

Three forward speeds, two reverse speeds and turning movements arecontrolled as follows:

With the control lever 74 in a vertical position, tiller cable 70 is insuch a position that tiller wheel 60 will be set so that the prime mover10 will follow a straight course. The control cable 82 will be in such aposition that contacts 137 will be riding on insulators 98 and currentwill not flow in the electrical circuit.

When switches 86 and '87 are closed and control lever 74 is pushedforwardly so that cable 82 moves insulated bar 134 to place contacts 137into contact with segment 97, 105, 113 and 124 a circuit is completedfrom L1 to L2 through conductor 204, relay 205, conductor 207, switch86, conductor 208, switch 87, conductor 209, segment 124, contact 136,contact carrier 133 and conductors 220a and 220 to L2. The currentflowing in relay 205 closes pole 206 and permits current to flow from L1through conductor 204, pole 206, contact 214, conductors 215, 227 and229, grid 226, conductors 230, 218 and 219, brushes 217 and 221, andconductor 220. This places the resistance of grid 226 in series with thearmatures of motors 30 and 31.

The resistance in grid 226 reduces the voltage to the armatures ofmotors 30 and 31 causing them to revolve at a speed forward which isslow enough for a person accompanying the wheel chair occupant to walkbeside the chair.

When the control lever 74 is pushed forwardly to position contacts 137on segments 96, 105, 113 and 124, an additional circuit is completed toL2 through relay 211. This closes pole 212 and takes the resistance grid226 out of the circuit and causes the motors 30 and 31 to speed up totheir second forward speed.

Since segments 96, 97 and 124 are connected to segments 100, 99 and 126respectively, it will be obvious that thetwo aforementioned speeds willbe imparted to the prime mover in a reverse direction of moving controllever 74 so that contacts 137 engage the sets of segments 99, 107, 115,and 126 and 100, 107, and 126, respectively.

A third forward speed is imparted to the device by moving the controllever 74 forwardly until contacts 137 engage segments 96, 105, 112 and124. This not only takes grid 226 out of the circuit in the manner abovestated, but also places resistance 237 in series with field coils 232and 231, thereby speeding up the motors 30 and 31.

When control lever 74 is tilted sidewise to the right, the tiller wheel60 turns the wheel chair A to the right. Conversely, when the controllever 74 is tilted to the left, the tiller wheel 60 turns the wheelchair A to the left.

It will be seen that the invention provides an improved prime mover forwheel chairs.

Many modifications and variations of the invention, as set forth herein,may be made without departing from the spirit and scope of theinvention. Accordingly, the drawings and specification herein are to beconsidered for purposes of illustration rather than of limitation.

I claim:

1. In a detach-able prime mover attachment for a wheel chair of tubularconstruction, said prime mover including a frame, a driving wheelrotatably mounted on said frame, and an electric motor in drivingengagement with said driving wheel, the improvement comprising a tillerwheel mounted on said frame, means for controlling flow of electricalcurrent to said motor and turning of said tiller wheel, said lastmentioned means including a control box, an articulated control levermounted in said box, a clamp on said box for clamping said box to saidwheel chair, a multi-pole electric switch mounted on said prime mover,said electric switch including segmental bus bars and electricalcontacts slidably engaging said bus bars, a first flexible cable havingone end connected to said switch for sliding said contacts over said busbars, and another end connected to said lever, and a second flexiblecable having one end connected to said tiller wheel and another endconnected to said lever.

2. A free-standing, detachable prime mover attachment for a wheel chairof tubular construction, said prime mover comprising a frame, wheelsrotatably mounted on said frame, a sprocket rigidly affixed to each ofsaid wheels, an electric motor aflixed to said frame for each of saidwheels, each of said motors including a shaft, a sprocket fixed to androtatable with each of said motor shafits, chain means connecting eachmotor shaft sprocket in driving engagement with each wheel, and meansfor controlling flow of electrical current to said motors and turningmovements of said tiller wheel, said last mentioned means including acontrol box, an articulated control lever mounted in said box, a clampon said box for clamping said box to said wheel chair, a multipoleelectric switch mounted on said prime mover attachment, said electricswitch including segmental bus bars and electrical contacts slidablyengaging said bus bars, a first flexible cable having one end connectedto said switch for sliding said contacts over said bus bars and anotherend connected to said lever, and a second flexible cable having one endconnected to said tiller wheel and another end connected to said lever.

3. The prime mover of claim 2 including also a clamp mounted on saidprime mover, said last mentioned clamp including a U-shaped frame, anaperture in each leg of said U-shaped frame, a slot connecting one ofsaid apertures to the exposed edge of one of said legs, a pin mounted insaid apertures, said pin having a reduced cross-section intermediate itsends, and a compression spring biasing said pin in such a manner thatsaid reduced cross-section is normally maintained out of engagement withsaid slot.

References Cited in the file of this patent UNITED STATES PATENTS MillsJune 14, 1949 8 Peterson et a1. Sept. 20, 1949 Duke 1 11.424, 1950Guyton Mar. 13, 1951 Steven Feb. 19, 1952 Anderson Feb. 10, 1953 WagnerDec. 1, 1953 Moederle June 14, 1 955 Kummer July 23, 1957

